[Pharo-project] [Vm-dev] Debugging Cog crash

Schwab,Wilhelm K bschwab at anest.ufl.edu
Fri Apr 8 21:25:27 CEST 2011


Levente,

It is indeed not the UUID plugin - Dave already suggested deleting it, and I tried that w/o success.

As for running gdb, I will gladly do so, but I have zero experience with it.  The most relevant posts I can find mention attaching to a vm that is already running, and I can't get that far.  Below is my attempt to modify the one-click shell script to run the vm under gdb.  Perhaps you or someone else can show me the errors of my ways and produce something that would yield a callstack.

Bill



#!/bin/sh

# path
ROOT=`dirname $0`
LINUX="$ROOT/Contents/Linux"
RESOURCES="$ROOT/Contents/Resources"

# icon
gvfs-set-attribute \
        "$0" \
        "metadata::custom-icon" \
        "file://$RESOURCES/Squeak.png" \
                2> /dev/null

# execute
gdb "$LINUX/squeakvm"

gdb run -plugins "$LINUX" \
        -encoding latin1 \
        -vm-display-X11 \
        "$RESOURCES/Pharo.image"


Levente wrote:

Well, the file OneClick.txt says the vm is "Linux Intel x86 4.0.3.2202". 
But that's not true, because that's not a CogVM.

The UUIDPlugin seems to have the patch which avoids the crash, so it's 
pretty unlikely that it's an issue with the UUIDPlugin. Even if the patch 
is wrong (which is unlikely, because we're using Eliot's latest build on 
64-bit Ubuntu 8.04 and it doesn't crash, but previous unpatched builds did 
crash), it's pretty unlikely that the cause of the crash is the related to 
UUIDPlugin at all, because UUIDs are normally not created during startup 
and your image is crashing on startup.
To be 100% sure you can try deleting UUIDPlugin and see if your image 
is crashing or not.
If it still crashes, then use gdb to see where it crashes. The VM seems to 
be unstripped (8MB), so it should be easy to identify the cause of the 
crash.


Levente


________________________________________
From: pharo-project-bounces at lists.gforge.inria.fr [pharo-project-bounces at lists.gforge.inria.fr] On Behalf Of Schwab,Wilhelm K [bschwab at anest.ufl.edu]
Sent: Friday, April 08, 2011 11:56 AM
To: Pharo-project at lists.gforge.inria.fr; Squeak Virtual Machine Development Discussion
Subject: Re: [Pharo-project] [Vm-dev] FW:  Debugging Cog crash

Levente,

The image will not load at all.  It simply dies with "Segmentation fault" - NOTHING else happens.  gdb is maybe a possibility, but it is not an approach I ordinarily take, so some guidance would be helpful.

I have a reproducible crash, but poor access to the affected box.

Bill



On Fri, 8 Apr 2011, Schwab,Wilhelm K wrote:

>
> Gratuitous default recipient...
>
> If there is a verbose dump option or other diagnostic efforts that will help, I will do my best to run them and report the results.  I am fairly certain the vm is 'Croquet Closure Cog VM [CoInterpreter VMMaker-oscog.54]' (can verify later today), but this happened with an earlier Cog one-click too.  There is something about the machine (UUID again?) that is different.  I do not have root access to it, but I can get to a terminal.  Ubuntu 10.10.

Where did you download the VM?
Does it crash when you're trying to evaluate [UUID new]?
Did you try gdb?


Levente





________________________________________
From: pharo-project-bounces at lists.gforge.inria.fr [pharo-project-bounces at lists.gforge.inria.fr] On Behalf Of Schwab,Wilhelm K [bschwab at anest.ufl.edu]
Sent: Friday, April 08, 2011 11:42 AM
To: Pharo-project at lists.gforge.inria.fr; Squeak Virtual Machine Development Discussion
Subject: Re: [Pharo-project] [Vm-dev] FW:  Debugging Cog crash

Dave,

It was, I did :)  No help :(  What else can I try?

Bill


________________________________________
From: pharo-project-bounces at lists.gforge.inria.fr [pharo-project-bounces at lists.gforge.inria.fr] On Behalf Of David T. Lewis [lewis at mail.msen.com]
Sent: Friday, April 08, 2011 10:32 AM
To: Squeak Virtual Machine Development Discussion
Cc: Pharo-project at lists.gforge.inria.fr
Subject: Re: [Pharo-project] [Vm-dev] FW:  Debugging Cog crash

Yes, the libuuid.so bug would be a likely suspect. If the UUIDPlugin was
built as an external library, just delete it and you will probably be
good to go.

If you need further info, look here:
http://bugs.squeak.org/view.php?id=7358

Dave

On Fri, Apr 08, 2011 at 07:58:39AM -0400, Schwab,Wilhelm K wrote:
>
> Gratuitous default recipient...
>
> If there is a verbose dump option or other diagnostic efforts that will help, I will do my best to run them and report the results.  I am fairly certain the vm is 'Croquet Closure Cog VM [CoInterpreter VMMaker-oscog.54]' (can verify later today), but this happened with an earlier Cog one-click too.  There is something about the machine (UUID again?) that is different.  I do not have root access to it, but I can get to a terminal.  Ubuntu 10.10.
>
>
> ________________________________________
> From: Schwab,Wilhelm K
> Sent: Friday, April 08, 2011 7:44 AM
> To: Mariano Martinez Peck
> Subject: RE: [Pharo-project] Debugging Cog crash
>
> Mariano,
>
> I first identified this problem/opportunity a while ago.  At the time, there was no log - the vm just died.  I can sniff around again as there might be one this time.  My question at the time was whether there was something that I could enable to perhaps get more info.
>
> The output from the vm is, and I quote<g> "Segmentation fault".  There is no other output.  Perhaps it does not get far enough to have a call stack??
>
> Bill
>
>
>
> ________________________________________
> From: Mariano Martinez Peck [marianopeck at gmail.com]
> Sent: Friday, April 08, 2011 3:42 AM
> To: Squeak Development Discussion Virtual Machine; Pharo Development
> Cc: Schwab,Wilhelm K
> Subject: Re: [Pharo-project] Debugging Cog crash
>
> also...shouldn't be a crash/dump file somewhere?
>
> can you write the output of the console where you invoke the VM into a file ?   (using > to redirect)
>
> Cheers
>
> Mariano
>
> On Thu, Apr 7, 2011 at 11:10 PM, Schwab,Wilhelm K <bschwab at anest.ufl.edu<mailto:bschwab at anest.ufl.edu>> wrote:
> Hello all,
>
> I have an account on an Ubuntu terminal server (at least I think that's what it would be called) running 10.10.  The Cog one-click image crashes with "Segmentation fault" (if run from a terminal); the legacy VM seems to run the image nicely on the box.  Any ideas?  I will happily collect any facts that will be of help, but I need some
> direction.
>
> Bill
>
>
>
>
>
>
> --
> Mariano
> http://marianopeck.wordpress.com






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